Rhubarb White Chocolate Elderflower Tart (Printable Version)

Crisp tart shell filled with white chocolate elderflower custard and roasted rhubarb. A stunning spring dessert.

# What You Need:

→ Tart Crust

01 - 1.5 cups all-purpose flour
02 - 7 tablespoons cold unsalted butter, cubed
03 - 3.5 tablespoons powdered sugar
04 - 1 large egg yolk
05 - 1 to 2 tablespoons cold water
06 - Pinch of salt

→ Custard Filling

07 - 5.25 ounces white chocolate, finely chopped
08 - 1 cup heavy cream
09 - 3.4 fluid ounces whole milk
10 - 3.4 fluid ounces elderflower cordial
11 - 3 large egg yolks
12 - 2.1 tablespoons granulated sugar
13 - 1 teaspoon vanilla extract

→ Rhubarb Topping

14 - 10.5 ounces fresh rhubarb, trimmed and cut into 2-inch batons
15 - 4.2 tablespoons granulated sugar
16 - Zest of 1 lemon
17 - 2 tablespoons elderflower cordial

# How to Make It:

01 - In a food processor, pulse together flour, cold butter, powdered sugar, and salt until the mixture resembles coarse breadcrumbs. Add egg yolk and 1 tablespoon cold water, then pulse until dough begins to form. Add additional water as needed. Shape into a disk, wrap in plastic film, and refrigerate for 30 minutes.
02 - Roll out chilled dough on a floured surface to fit a 9-inch tart tin. Press dough into tin and trim edges. Refrigerate for 15 minutes. Preheat oven to 350°F. Line crust with parchment paper and baking beans. Blind bake for 15 minutes. Remove beans and parchment, then bake 5 to 7 minutes more until golden brown. Cool completely.
03 - Heat heavy cream and milk in a saucepan until steaming but not boiling. Whisk egg yolks, sugar, and vanilla extract in a separate bowl until pale. Gradually pour the hot cream mixture into the yolks while whisking constantly. Return mixture to saucepan over low heat, stirring until slightly thickened to coat the back of a spoon. Remove from heat, add chopped white chocolate and elderflower cordial, and stir until completely smooth.
04 - Pour the custard filling into the cooled tart shell. Refrigerate for at least 1 hour until set and firm to the touch.
05 - Preheat oven to 375°F. Arrange rhubarb batons in a single layer in a baking dish. Sprinkle with sugar and lemon zest, then drizzle with elderflower cordial. Cover with foil and roast for 15 minutes. Remove foil and roast 5 to 8 minutes more until tender but still holding shape. Cool completely.
06 - Arrange cooled rhubarb over the set custard filling. Optionally brush with additional elderflower cordial for a glossy finish. Refrigerate until ready to serve.

# Expert Advice:

01 -
  • The contrast between tangy roasted rhubarb and sweet white chocolate custard creates a flavor balance that feels both elegant and comforting.
  • You can make every component a day ahead, which means zero stress when guests arrive.
  • It looks like something from a patisserie window but comes together with straightforward techniques.
  • The elderflower cordial adds a subtle floral note that makes people ask what the secret ingredient is.
02 -
  • Do not skip chilling the tart dough before rolling, warm dough shrinks dramatically in the oven and can pull away from the edges.
  • Tempering the egg yolks slowly is critical, if you rush the hot cream in all at once, you will end up with sweet scrambled eggs instead of custard.
  • Watch the rhubarb closely during the final uncovered roasting, it can go from tender to mushy in just a minute or two.
03 -
  • Freeze the tart shell for 10 minutes before blind baking to help it hold its shape and prevent shrinkage.
  • Stir the custard constantly in a figure eight motion while cooking to prevent hot spots and ensure even thickening.
  • Use a pastry brush dipped in elderflower cordial to glaze the rhubarb right before serving, it adds shine and intensifies the floral flavor.
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